Wrapper closed by twist wraps and wrapping method

ABSTRACT

A packaging wrapper consisting of a film intended to be closed by two twists on either side of an article to be packaged, characterized in that the film comprises, on the internal side in relation to the article to be packaged, a sealing coating placed along two transverse strips on either side of the article to be packaged and extending parallel to an axis passing through the two twists. The film may additionally comprise two lengthwise strips of sealing coating extending on either side of the strips of sealing coating extending on either side of the article to be packaged, perpendicularly to the said transverse strips in the regions of formation of the twists. These sealing coatings may be either cold-sealing coatings or heat-sealing coatings.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of International Application No.PCT/EP97/05256, which claims priority from European Application No.EP96202789.2 filed Oct. 8, 1996.

FIELD OF THE INVENTION

The present invention relates to a packaging wrapper consisting of afilm intended to be closed by two twists on either side of an article tobe packaged, and to a process for packaging an article with the aid ofsuch a package. In particular, the invention relates to the field of thepackaging of confectionery products.

BACKGROUND OF THE INVENTION

Confectionery are generally packaged individually in a preprinted pieceof film of an appropriate size and shape, it being possible for the saidindividually packaged products to be, in their turn, packed in bulk in asmall packaging bag of an appropriate size. The article to be packagedis typically first of all completely wrapped in a rectangular piece offilm and the package thus formed is closed by twists at two pointssituated on either side of the article to be packaged.

In the context of the present invention a twist is intended to mean theresult of the closure by twining of the said wrapper.

An important problem which presents itself in this respect is that ofthe retention of the twist. This retention can be obtained only at thecost of a particular selection of the film employed as substrate, whichmust exhibit appropriate mechanical characteristics such as pliabilityor, in particular, a pronounced tendency not to return to its initialposition after the twining of the said film.

In particular, this problem becomes apparent when articles of smallsizes and of essentially round section are being packaged, such asconfectionery products like, for example, bonbons, lollipops, barleysugar, fruit jellies, chocolate-coated bars or else more bulky productssuch as bottles, rolls of articles, etc.

As solution, it is known to select particular substrates which are knownfor their high pliability, like waxed paper or cellophane or syntheticfilms containing an appropriate quantity of an additive increasing thepliability of the said substrate.

This solution considerably restricts the potential choices of filmsemployed as packaging substrate and considerably increases their cost.

Packages closed by twists, which are produced from substrates precoatedwith a heat-sealing coating, are known on the market. When twists arebeing formed at the ends of the wrapper containing the article to bepackaged, a source of heat at a temperature of approximately between 120and 160° C. is approached for a certain period of time. In general, itis the jaws performing the twining that are heated, but it is alsopossible to blow hot air by means of a pipe of appropriate size onto thesaid twists, and this results in the melting of the heat-sealing coatingand the sealing of the twist thus formed when the said heat-sealingcoating is cooled.

Document GB-A-1096058 proposes a film with a cold-sealing coating whichexhibits an excellent retention after closure of the wrapper by twiningof the twists. This cold-sealing coating is in the form of twolengthwise strips situated in the regions of formation of the twists oneither side of the article to be packaged.

Cold-sealing is intended to mean sealing which takes placeinstantaneously merely by contact at a temperature of approximatelybetween 0 and 50° C. In reality, the temperature is not a criticalparameter for obtaining sealing by means of a cold-sealing coating andhas practically no effect on the quality of the sealing obtained. Thesealing is therefore performed without an additional heat input beingnecessary at the ambient temperature of the space in which the packagingunit is situated.

This method therefore makes it possible to employ films which are lessexpensive and have better properties (rigidity, printability, aestheticqualities) for the packaging of articles without any restrictions as tothe shape or the heat-sensitivity of the said articles.

SUMMARY OF THE INVENTION

The objective of the present invention is to provide a novel packagingof the type with closure by twists, which allows a better closure thanthe currently known packages, as well as a novel packaging process.

To attain this objective the present invention provides a packagingwrapper consisting of a film intended to be closed by two twists oneither side of an article to be packaged, characterized in that the filmcomprises, on the internal side in relation to the article to bepackaged, a sealing coating placed along two transverse strips on eitherside of the article to be packaged and extending parallel to an axispassing through the two twists.

The said sealing coating may be a cold-sealing coating or a heat-sealingcoating.

The film may additionally comprise two lengthwise strips of sealingcoating extending on either side of the strips of sealing coatingextending on either side of the article to be packaged, perpendicularlyto the said transverse strips in the regions of formation of the twists.These sealing coatings may also be either cold-sealing coatings orheat-sealing coatings. When the substrate of the film has a lowresistance to elevated temperatures and/or when the article to bepackaged is heat-sensitive, especially products of chocolatemanufacture, the cold-sealing coating deserves to be preferred.

The heat-sealing coating may be a layer of PE (polyethylene) coextrudedonto OPP (oriented polypropylene).

As cold-sealing coating, it is possible to envisage pressure-sensitiveadhesives, which are substances which are continually adhesive and whichadhere spontaneously to the surface of most materials under the effectof a simple moderate pressure.

As a general rule the pressure-sensitive adhesives are compositionsbased on natural and/or synthetic rubber, used in combination withmodified cellophanes, phenol-formaldehyde resins or hydrocarbon resins(waxes). Besides rubbers, polymers based on styrene, (meth)acrylic acidor vinyl ether are widely employed, alone or as a mixture, also incombination with resins. Lastly, silicone resins may also be employed.Compositions including mixtures of natural and synthetic rubbers andcopolymers of (meth)acrylic acid and styrene are preferably employed.

These cold-sealing coatings are deposited onto the substrate at a rateof approximately from 1 to 5 g/m². They can be applied in the form ofsolution or dispersion or even in the molten state. Coating depositiontechniques which are well known to a person skilled in the art may beemployed, such as, for example, heliographic or flexographic printing orelse offset printing.

The invention also proposes a process for packaging an article in a filmcomprising at least two transverse strips of a sealing coating,according to which the article is deposited on the film on the side ofthe said strips and between the latter, the two sections which areprovided with the said strips of coating are raised substantiallyvertically, the two sections are brought close on top of the article andtheir edges are sealed to one another, the two edges thus sealed arefolded back over the article and the projections of the film extendingbeyond on either side of the article are twined to form two twists.

When the strips of coating comprise a cold-sealing coating, theoperation of folding and sealing the edges of the strips on top of thearticle is preferably carried out as a single operation between the jawsof a press.

When the coating is a heat-sealing coating, the edges are sealed to eachother by a heat-sealing process.

The invention has the advantage that, for the first time, the package ofthe twist-closure type is sealed in the transverse direction between thetwo twists. Given that even the packages without lengthwise coating inthe regions of formation of the twists have a leakproofing which israther good at the twists, packages which are completely closed are thusproduced.

With regard to the packages provided with lengthwise regions of heat- orcold-coating, in the case of which there is a leakproof closure at thetwists, a virtually hermetic closure is produced by virtue of thetransverse sealing. This complete closure of the package is veryadvantageous with regard to the conservation of the articles, since itprevents the entry of moisture, of gas, of air or of other harmfulsubstances and, at the same time, preserves the flavours within thepackaging.

The invention will be understood better on reading the description of afew embodiments which are presented below, by way of illustration, withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the present invention, andtogether with the description serve to explain the principles of theinvention. In the drawings:

FIG. 1 shows diagrammatically a plan view of a first embodiment of apackage according to the present invention;

FIG. 2 shows diagrammatically a plan view of a second embodiment of apackage according to the present invention;

FIGS. 3a, 3 b, 3 c and 3 d show the successive sequences of packaging ofan article with the aid of a package according to the present invention;

FIGS. 4a, 4 b, 4 c and 4 d show, in perspective views, the varioussequences of packaging;

FIGS. 5 and 6 show the sealing and the folding of the packagingaccording to the present invention in the transverse direction parallelto the axis passing through the twists.

While the invention will be described in connection with certainpreferred embodiments, there is no intent to limit it to thoseembodiments. On the contrary, the intent is to cover all alternatives,modifications and equivalents as included within the spirit and scope ofthe invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a strip of film indicated overall by reference 10, which isa film with a good retention where the twining alone suffices to obtaina rigid twist which does not open, that is to say a substrate which doesnot require an adhesive bonding coating for retaining the twists. Such afilm may, for example, be a cellophane film, a cast PP (castpolypropylene) film, waxed paper, an aluminum/OPP laminate and the like.

The articles to be packaged are shown using broken lines by reference12. The strip of film 10 is intended to be cut along the lines 14 toprovide pieces of film 16 which are identical with each other, which actas packaging wrappers for the articles 12. The outline of the twists 18obtained by twining the projections on either side of the article to bepackaged 12 has also been shown using broken lines in FIG. 1.

In accordance with the present invention the strip of film 10 comprisessealing coatings 20 extending in the transverse direction of the stripon the internal side in relation to the articles 12 to be packaged.These strips 20 are placed straddling the cut lines 14 so that aftercutting of the strip of film 10 each individual piece 16 comprises twotransverse strips 20 a, 20 b of sealing coating along its edges.

In the example shown in FIG. 1 the sealing coating is a cold-sealingcoating, for example the product 22-392 of the company Croda, which isdeposited at a rate of 3 g/m².

FIG. 2 shows a second embodiment of a packaging film 40 according to thepresent invention. This film 40 consists of coexOPP (coextruded orientedpolypropylene) which on its own does not have any properties ofretention of the twists 18. Nevertheless, to make it possible to formthese twists 18 the film is coated in the two regions of formation ofthe twists 18, on the internal side in relation to the product to bepackaged 12, with two lengthwise strips 42, 44 of a cold-sealing coatingwhich may consist of the same material as that of the transverse strips20 of the embodiment of FIG. 1. The embodiment of FIG. 2 comprisestransverse strips 46 of heat-sealing coating which form transversestrips 46 a and 46 b along the edges of each piece after the film hasbeen cut. These transverse strips of heat-sealing coating may be formedby a layer of PE coextruded onto the OPP.

It should be noted that various combinations are possible between theembodiments according to FIGS. 1 and 2. Thus, for example, thetransverse strips of cold-sealing coating of FIG. 1 may be replaced bytransverse strips of heat-sealing coating. Similarly, the heat-sealingstrips 46 in FIG. 2 may be replaced by cold-sealing strips. Furthermore,it is possible that both the lengthwise strips 42, 44 in FIG. 2 and thetransverse strips 46 may all consist either of heat-sealing coating orof cold-sealing coating.

FIGS. 3a to 3 d and FIGS. 4a to 4 d illustrate the various successivestages of a process of packaging in accordance with the presentinvention with the aid of a package as described above with reference toFIGS. 1 or 2. The article 12 is placed on one of the film foils 16within the transverse strips 20 a and 20 b. The pieces of film 16 ofFIG. 1 have been shown, by way of example, in the figures, but it is tobe understood that the process applies equally well to the film of FIG.2 and to the various possible combinations. The two side sections A andB with the transverse strips of sealing coating 20 a and 20 b are nextfolded upwards as shown in FIGS. 3a and 4 a. The two sections A and Bare next folded simultaneously inwards over the article 12 so that theirinternal edges with the transverse strips 20 a and 20 b are placedagainst one another as shown in FIG. 4b. A pressure is next exerted, asshown in FIG. 5, on the outside of each of the edges of the sections Aand B over the whole width in order to seal these two sections welltogether at their cold-sealing coating. This operation of folding thesections A and B and of sealing their edge may be performed as a singleoperation between the jaws of a press 48 (FIG. 3b). A sealing rib 50 isthus obtained, which extends over the whole width, as shown in FIGS. 3cand 4 b. This rib is next folded and folded back over the packageaccording to FIGS. 3d and 4 c, preferably, by applying a verticalpressure according to FIG. 6 to give the package an attractivepresentation. The package is finished by twining the two ends in thedirection of the folding back of the rib 50 to form two twists 18according to FIG. 4d.

By virtue of the presence of the transverse strips 20 a, 20 b ofcold-sealing coating and by virtue of the use of pressure, a perfectclosure is obtained over the whole width of the package. In addition,the twists 18 ensure a side closure, above all when they are made at thelengthwise strips 42 and 44 of sealing coating according to FIG. 2. Avirtually hermetic package is thus produced, which prevents the exit ofthe flavours or the entry of air, of moisture, of detrimental odours andthe like.

In the case of transverse strips of heat-sealing coating the jaws of thepress 48 may be heated to a temperature of the order of 150° to obtainperfect sealing between the strips 20 a and 20 b. It is also possible toblow hot air (±150-180° C.) onto the two edges before they are sealedtogether in the press.

What is claimed is:
 1. A process for packaging an article in foils of afilm, each foil extending in longitudinal and transverse directions andhaving two transverse strips of a sealing coating along two transverseedges and two longitudinal strips of sealing coating extending on eitherside of the article to be packaged and perpendicular to the transversestrips in the regions of formation of the twists at a distance from thelongitudinal edges of the foil, the ends of the transverse strips beingspaced from the longitudinal edges a distance corresponding to thedistance the longitudinal strips are spaced from the longitudinal edges,the process comprising: depositing the article between the transversestrips and between the longitudinal strips on a side of the foil havingsaid strips to leave excess film extending beyond the article: raisingthe two transverse edges substantially vertically; positioning the twotransverse edges proximate one another on top of the article; sealingthe transverse edges to one another by the two transverse strips;folding the two transverse edges thus sealed back over the article; andtwisting the excess film in the area of the longitudinal strips to formtwo twists.
 2. The process according to claim 1, wherein the operationof folding and of sealing the transverse edges above the article iscarried out as a continuous operation between sealing of jaws of apress.
 3. A packaging wrapper comprising a film which can be cut intoseparate foils, each foil sized to be closed by two twists on eitherside of an article to be packaged, the film including on one side and oneach foil two longitudinal strips of sealing coating and two transversestrips of sealing coating, the two transverse strips extending betweenthe longitudinal strips along two transverse edges of the foil, the twolongitudinal strips extending on either side of the article to bepackaged and perpendicular to the transverse strips in the regions offormation of the twists at a distance from the longitudinal edges of thefoil, the ends of each transverse strip being spaced from thelongitudinal edges a distance corresponding to the distance thelongitudinal strips are spaced from the longitudinal edges.
 4. A wrapperaccording to claim 3, wherein the coatings are a cold-sealing coating.5. A wrapper according to claim 3, wherein the coatings are aheat-sealing coating.
 6. A wrapper according to claim 3, wherein the twolongitudinal strips are of cold-sealing coating and the two transversestrips are of heat-sealing coating.
 7. A wrapper according to claim 3,wherein the two longitudinal strips are of heat-sealing coating and thetwo transverse strips are of cold-sealing coating.
 8. A wrappercomprising a film which can be cut into separate foils, each foil to beclosed by two twists on the sides of an article to be packaged, the filmincluding on one side and each foil, two longitudinal strips of sealingcoating, and two transverse strips of sealing coating extendingperpendicularly to the longitudinal strips along two transverse edges ofthe foil, the longitudinal strips being spaced at a distance from thelongitudinal edges, the ends of the transverse strips being spaced fromthe longitudinal edges and extending between the longitudinal strips,wherein the two transverse strips are of cold-sealing coating.
 9. Awrapper according to claim 8, wherein the coatings are a cold-sealingcoating.
 10. A wrapper according to claim 8, wherein the twolongitudinal strips are of heat-sealing coating and the two transversestrips are of cold-sealing coating.